Ulmann's Encyclopedia of Ind. Chem., Vol. A24, 107 (1993) discloses that since silver, which is precious metal, is not easily oxidized but has excellent electric and thermal conductivity and further has a catalyst, an antibacterial activity and so on, silver compound such as silver (Ag) and silver oxide has been widely used in the industry overall such as electrode material, alloys, platings, medicaments, photographs, electric/electronics, fibers, detergents, home appliances, and so on.
Silver oxide is a compound stable at a normal temperature, but has a feature that it is reduced into silver (Ag) using a decomposition by heating. A reduction reaction begins at 160° C., however the silver oxide having a slow response speed is required to be heated at 400° C. or more in order to give conductivity after the reduction is completed.
Japanese Patent Laid-Open No. Sho 56-69309 discloses the method to prepare silver oxide by adding aqueous silver nitrate (AgNO3) solution into aqueous sodium hydroxide (NaOH) solution and then precipitating it. However, this method has disadvantage in that it is difficult to be dispersed and reduced at a low temperature due to aggregation. And, U.S. Pat. No. 7,201,888 discloses the method to prepare nano-sized silver oxide using silver nitrate (AgNO3) and sodium hydroxide (NaOH) as oxidant and using fatty acid as surfactant on aqueous solution. However, this method fails to disclose a method to prepare particles of various shapes.